This study aimed to enhance senior students' financial literacy, specifically in the areas of sinking funds and amortization, through an intervention known as the 4Is and 4Ys, which follows a scaffolding approach. The research employed a quantitative method using a one-group pretest-post-test design, a type of pre-experimental approach where the same group of participants is assessed before and after the intervention (Fraenkel et al., 2015). Prior to the intervention, students recorded an overall mean score of 25% in the pretest, indicating poor financial literacy skills. After implementing the intervention, the posttest results showed a significant improvement, with an overall mean score of 90.75%, suggesting a highly effective impact of the 4Is and 4Ys strategy on students’ learning outcomes. The data, as presented in the results table, reflect a marked difference in the performance of 20 students in computing sinking funds and amortization. This notable improvement demonstrates the effectiveness of the intervention in helping students build foundational knowledge and apply complex financial concepts more confidently. Initially, students struggled with these topics, showing limited understanding and skills. However, following the structured and supportive learning process offered by the 4Is and 4Ys approach, their performance improved considerably. These findings highlight the value of targeted instructional strategies in addressing specific learning gaps among students. Moreover, results showed that students performed better in the post-test than the pre-test, implying a significant difference between the two test scores, t(19) = 23.2, p<.001, with a standardized effect size of Cohen’s d=5.18. Since the probability value (p < .001) is less than the level of significance (α = 0.05), the null hypothesis is rejected. The rejection is supported by having a standard deviation of 2.54, indicating the reliability of the mean. This means that there is a significant difference between the pretest and post-test scores. In the qualitative phase, the researchers gained insights about the positive outcome of the intervention together with the challenges faced by the students. The study concludes that scaffolding methods like 4Is and 4Ys can significantly contribute to developing senior high schoolh students’ financial literacy, making complex topics more accessible and enhancing their problem-solving abilities in real-life financial situations